N.J. Stat. § 19:29-14
The contestant and incumbent shall be liable to the officers and witnesses for the costs made by them, respectively. If the election be confirmed, or the petition dismissed, or the prosecution fail, judgment shall be rendered against the contestant for costs; and if the judgment be against the incumbent, or the election be set aside, he shall pay the costs at the discretion of the court; and in the case a contestant is successful in contesting the approval or disapproval of a proposition, the State, county or municipality, as the case may be, which caused the proposition to be submitted to the voters, shall pay the costs at the discretion of the court. After the entry of the judgment of the court the costs may be collected by attachment or otherwise.
N.J.S. § 19:29-14